1. Field of the Invention
The present invention relates to a hand-held electronic apparatus, a so-called IC cards which are used as credit cards, cash cards, transaction cards, debit cards, etc.
2. Description of the Prior Art
Cards having a magnetic strip on their reverse sides have been known for quite some time. They are used as bank cards, credit cards, cash cards, etc. On the magnetic strip there is encoded various account information which may include a password, account type designator, etc. There is now considerable interest in utilizing a more intelligent card in place of the magnetic strip type card. The more intelligent card has at least one integrated circuit (IC) chip embedded in it. The card includes a programmable non-volatile memory, and a control element such as a CPU for controlling the memory and the like. With this IC card, transaction account data stored in the memory is read by a terminal to perform a transaction.
As disclosed in U.S. Pat. No. 4,697,072, the subject matter of which is incorporated by reference as if fully set forth herein, and U.S. Pat. No. 4,614,861, the subject matter of which is incorporated by reference as if fully set forth herein, a card which incorporates a battery and includes a keyboard and a display has been developed. Such a card can be used alone without being connected to a terminal.
European Patent Disclosure No. 0 167 044 (published) discloses an IC card with a timepiece for displaying timepiece data such as date and time, and a calculator for performing arithmetic operations. However, in the European Patent Disclosure IC card, the IC's display is not turned off in an initial state. U.S. Pat. No. 3,813,533, the subject matter of which is incorporated by reference as if fully set forth herein, discloses an apparatus having both timepiece and calculator functions. It is a rather compact device that includes both an electronic calculator and a timepiece. When a power switch of the card is turned on, a calculator mode is set. A special purpose key is provided for causing the device to operate in a timepiece mode. When that special purpose key is pressed while the device is operating in its calculator mode, the device changes its mode of operation and begins to operate in its timepiece mode. When the special purpose key is again pressed, while the device is operating in the timepiece mode, the device again operates in its calculator mode.
Some devices operate in a timepiece mode only while a special purpose key is maintained pressed after the power switch is turned on. In conventional devices, a special-purpose key is generally provided for causing the device to operate in a timepiece mode. This special purpose key must be operated each time the device is to be operated in the timepiece mode.
For battery powered IC cards, it is desirable to minimize battery drain to extend its useful life. Therefore, battery power must be conserved where possible. However, in conventional devices of this type, no particular means are provided for conserving battery life.